A control or shut-off valve, especially a water valve, can comprise a valve body formed with the radial inlet and outlet and a valve unit which can be insertable in this valve body.
The valve unit, which can be referred to as a cartridge because it contains the sealing elements and valve mechanism in a housing which can be replaced as a unit in the valve, can comprise a valve seat disk extending transversely to the longitudinal axis about which a valve spindle is rotatable in the housing, the valve seat disk having at least one throughgoing opening and being nonrotatably held in the housing. A valve control disk is rotatable in the housing for the valve spindle and lies upstream of the valve seat disk and the valve control disk may be stressed by a spring against the valve seat disk. The two valve disks extend across the inlet opening in the housing and between the supply passage of the valve and the housing, a sealing element can be provided. A valve of this type is described in German Open Application DE-OS 3107431.
The valve unit with its housing is so constructed, in this system, that it can also be used in already installed valves that originally may have had other types of standard valve mechanisms with axially shiftable closure parts.
In the valve system of this patent document, however, the valve seat disk is braced only against an outer annular shoulder of the housing so that a relatively thick plate must be used as the valve seat disk to prevent deformation and distortion under the water pressure and spring pressure which may be applied.
In spite of the thickness of the valve seat disk employed, however, it is not possible to guarantee, in this construction, that pressure shocks applied to the valve seat disk will not bend or deform the latter and thereby give rise to leakage and even rupture of the valve seat disk.
Another drawback of this earlier system is that the spring, required to maintain a minimum pressing force for holding the valve control disk against the valve seat disk, is located in the water flow region of the inlet opening which has proved to be a highly disadvantageous locale for such a spring.
U.S. Pat. No. 2,923,318 illustrates a shut-off and control valve in which valve units are receivable in specially shaped receiving bores of the valve body. The valve seat disk in inserted from the downstream side and is supported by a coaxially oriented tubular pin. In this construction as well, bending by pressure or shock forces of the valve seat disk cannot be precluded and it is also possible that the forces applied will generate a distorting stress on the valve seat disk. Another drawback of this latter system is that the valve must be assembled from a relatively large number of complex parts so that even the housing must be bypartite.